The Changes of Renal Function in Apparent Healthy Individuals with a Simple Renal Cyst

Korean Journal of Nephrology 2007;26(5):554-558.

Hyung Suk Lee, M.D., Seong Gyun Kim, M.D., Eun Jung Kim, M.D. Young-Rim Song, M.D., Soo Jin Kim, M.D., Ji-Eun Oh, M.D. Young-Ki Lee, M.D., Jang Won Seo, M.D., Jong-Woo Yoon, M.D. Ja-Ryong Koo, M.D., Jung-Woo Noh, M.D. and Hyung Jik Kim, M.D.

Department of Internal Medicine and Kidney Research Institute, Hallym University College of Medicine, Anyang, Korea

The Changes of Renal Function in Apparent Healthy Individuals with a Simple Renal Cyst

Department of Internal Medicine and Kidney Research Institute, Hallym University College of Medicine, Anyang, Korea

Abstract

Purpose : Simple cysts are a common structural abnormality in seemingly healthy individuals, but their clinical significance, especially on changes of renal function, remains unknown. We examined whether sporadic cysts can influence changes of renal function in apparent healthy individuals. Methods : The records from 424 people who underwent two ultrasonographic examinations in a routine check-up at our health promotion center from 2000 to 2003 were reviewed. Patients who had a medical disease were excluded. The healthy individuals (n=199) were divided into two groups according to whether they had renal cysts (cyst group, n=61), or not (control group, n=138). Renal function was evaluated by serum creatinine level (Scr), creatinine clearance (Ccr), using the Cockcroft-Gault equation, and glomerular filtration rate (GFR), using the MDRD equation. Results : Individuals in the cyst group were significantly older (44.18±7.55, 41.02±7.06, p=0.013) and more likely to be male (90.16%, 72.46%, p=0.006) than those without cysts. Compared with the control group, the cyst group had no significant differences in Scr (1.03±0.15 mg/dL, 1.08±0.11 mg/dL, respectively, p=0.06), in Ccr (82.34±13.26 ml/min, 81.00±12.6 ml/min, respectively, p=0.56) nor in GFR (84.35±11.65 ml/min/1.73m2, 82.47±10.27 ml/min/1.73m2, respectively, p=0.38). Furthermore, the parameters for changes of renal function were not significant over three years. Conclusions : The presence of renal cysts was associated with neither renal dysfunction nor a reduction in renal function over three years in Korean individuals without apparent renal disease.

Key Words: Kidney diseases, cystic, Glomerular filtration rate, Kidney function tests